The present invention relates to a means for affixing two structural members together, and, more particularly, to a plug that can be inserted into the enlarged portion of a keyhole slot to prevent the inadvertent detachment of those structural members.
A common method of affixing together structural members is by use of a keyhole slot that is formed in one of the members, into which is inserted a standoff rivet extending from the other member. Basically, the keyhole slot is one that has an enlarged portion and a narrowed portion extending therefrom. The enlarged portion may be a variety of geometrical configurations, including square, oval and the like but is preferably a round or circular shape. It is only important that the configuration and geometry of the enlarged portion be sufficiently sized to allow the head of the standoff rivet to pass therethrough.
The narrowed portion of the keyhole slot is generally an elongated oval configuration that is sized to allow the body of the rivet to slide therealong to a closed end but not allow the head of the standoff rivet to pass therethrough. While the elongated oval configuration of the narrowed portion may have parallel sides, the sides may also slightly taper inwardly in the direction of the closed, circular end.
Thus the joint between the two structural members is accomplished by simply inserting the head of the standoff rivet through the enlarged portion of the keyhole slot and displacing the members with respect to each other to slide that standoff rivet to the affixed position where the body of the rivet is relocated to the closed end of the narrowed portion, thereby joining the members together. As used, herein, the term xe2x80x9cstandoff rivetxe2x80x9d will be used generically and the actual component can be any of a variety of projections that extend outwardly from one of the structural members having a smaller dimensioned portion and an outer, distal portion having larger dimensions and the actual configuration of the standoff rivet may be circular, square of any of a number of differing geometries.
One of the difficulties of such connections between structural members is that they may become loose, that is, the standoff rivet, once slid into the affixed position, can later move inadvertently such that the head of the standoff rivet is again aligned with the enlarged portion of the keyhole slot and can come loose, thereby causing the members to come apart.
There have been proposed a number of plugs that can interfit with two openings in structural members to prevent the relative movement between those members, including U.S. Pat. No. 3,392,848 of McConnell et al where a dual locking pin arrangement is utilized where one of the locking pins holds the device in the desired position while the other of the locking pins enters corresponding, aligned holes between the two structural members. The device, however, requires two plugs and also a metal spring that joins those two plugs together and therefore is not a simple, one piece molded part that can prevent relative movement between two structural members.
As another example, a metal spring clip device is shown and described in Klein, U.S. Pat. No. 5,131,781 that assists in the connection between a beam and a column and again, the device requires the alignment of two apertures through which a pin enters. Other devices of the type are constructed as a part of a locking mechanism or are spring loaded devices that pass between aligned members, such as shown in Olsen, U.S. Pat. No. 5,938,367 and Kautz et al, U.S. Pat. No. 6,241,109.
Accordingly, it would be advantageous if there were a device, such as a one piece, molded plug, that could be inserted into the keyhole slot to prevent the relative movement between the structural members and thus also prevent the inadvertent detachment of the members. It would be further advantageous for the plug to be inexpensive and yet be firmly and easily inserted into the keyhole slot to serve the aforementioned purpose by self locking in the enlarged portion of a keyhole slot formed in a structural member and which interfits with a standoff rivet in the other of the structural members.
Now, in accordance with the present invention, there is provided a relatively inexpensive plug to lock together two structure members that are affixed together by means of a standoff rivet of one structural member that is inserted into the enlarged portion of a keyhole slot in another structural member such that the junction between the structural members is accomplished by sliding the standoff rivet along the keyhole slot to be located at the closed end of the narrowed portion of the keyhole slot.
The plug of the present invention is shaped so as to remain affixed within the enlarged portion of the keyhole slot. The device is affixed into that enlarged portion by means of a pair of flexible latches that are molded into the main body of the plug and which are preferably biased outwardly. As such, the plug can be inserted easily into the enlarged portion of the keyhole slot and the flexible latches snap onto the thickness of a structural member to easily but firmly hold the plug into the affixed position.
The plug is constructed of predetermined dimensions such that it physically interferes with the movement of the standoff rivet from its position at the closed end of the narrowed portion of the keyhole slot. By means of the plug, there are opposed surfaces that are a predetermined distance apart. One of those opposed surfaces is located at or near the standoff rivet and physically prevents the movement of the standoff rivet along the narrowed portion of the standoff rivet to the enlarged portion of the keyhole slot where the standoff rivet could become detached.
Preferably, the external surface of plug that faces the standoff rivet is arcuate so as to provide a good contact with that circular rivet. The opposed surface opposite the surface facing the standoff rivet engages the enlarged portion of the keyhole slot such a solid barrier is present to prevent the relative movement between the two structural members and therefore secures the structural members together in a fixed, locked relationship.
Other features of the present device and junction between structural members utilizing the device will become apparent in light of the following detailed description of the a preferred embodiment thereof and as illustrated in the accompanying drawings.